Aim TransCon CNP is a novel prodrug designed to provide sustained release of C‐type natriuretic peptide (CNP) for once‐weekly therapy, addressing the pathology leading to aberrant skeletal development in achondroplasia. This phase 1 trial was initiated to assess the safety, tolerability, pharmacodynamics (PD) and pharmacokinetics (PK) of TransCon CNP. Methods This randomized, placebo‐controlled, single‐ascending dose phase 1 trial was performed at two sites in Australia and enrolled 45 healthy adult males. Subjects received placebo or TransCon CNP (single‐ascending dose cohorts [3, 10, 25, 75 or 150 μg CNP/kg]). The primary endpoint was frequency of adverse events and other safety outcomes. Other endpoints included PK and PD measured by cyclic guanosine‐monophosphate (cGMP) and amino‐terminal propeptide of CNP (NTproCNP). Results TransCon CNP provided continuous systemic exposure to CNP over at least 7 days post‐dose. Plasma and urine levels of cGMP were significantly increased in subjects administered TransCon CNP at 75‐150 μg CNP/kg, indicating target engagement of active CNP at the natriuretic peptide receptor‐B (NPR‐B) for at least 1 week post‐dose. TransCon CNP was well‐tolerated, with no serious treatment‐emergent adverse events or discontinuations. Extensive cardiac safety assessments did not reveal any clinically relevant effects on electrocardiogram parameters, including heart rate, PR, QRS and QTcF intervals. Conclusions Safety and PD data from this phase 1 trial support that TransCon CNP is well tolerated, with a PK profile compatible with a once‐weekly dosing regimen. Further studies are ongoing to evaluate the potential of TransCon CNP to positively impact abnormal endochondral ossification in children with achondroplasia.

The study aimed to explore how having achondroplasia affects older children and adolescents' day-to-day functioning and well-being. Individual/focus group interviews were conducted with older children/adolescents between the ages of 9 to <18 years and diagnosed with achondroplasia to elicit key concepts. An adapted grounded theory approach informed the qualitative analysis of interview data. Thirty-two children and adolescents completed interviews. Study results revealed five impact domains, including physical health, functioning, school impacts, emotional well-being, and social well-being. Frequently reported impacts on physical health included low stamina/tiring easily (81%) and back pain (69%). Key impacts in the functioning domain were difficulty with reaching objects or high places (84%) and walking long distances (75%). Emotional impacts included feeling different (63%), worried/scared (47%), and embarrassed/self-conscious (47%). Impacts on social well-being included difficulty with sports or physical play (81%) and others treating child as younger than their actual age (75%). The most frequent school impact was trouble participating in physical education (81%). A preliminary theoretical model depicting the experiences of older children/adolescents with achondroplasia was constructed based on the analysis. The preliminary theoretical model of older children and adolescents' experiences of living with achondroplasia may be used to inform future research and clinical practice.

Background Currently, there is limited research on how having a child diagnosed with achondroplasia affects parents’ lives. The purpose of the study was to investigate the experiences of parents of infants and young children less than two years of age with achondroplasia. Methods Concept elicitation interviews were conducted with parents of children less than 2 years of age with achondroplasia in the United States and Spain. Using grounded theory methods modified for health outcomes research, a qualitative analysis of interview transcripts was conducted. Based on the qualitative analysis, a preliminary theoretical model of the experiences of parents of infants and young children with achondroplasia was developed. Results Fifteen parents, including 14 mothers and 1 father from 15 unique families, participated in individual or focus group concept elicitation interviews in the US (n = 9) and Spain (n = 6). The qualitative analysis identified four key parent impact domains, which included caretaking responsibilities, impacts on emotional well-being, having worries and concerns about their child, and impacts on daily well-being. Frequently discussed caretaking responsibilities among parents were managing child’s medical care/treatment (93%), obtaining adaptations/items for child (73%), and monitoring child to avoid complications of achondroplasia (67%). Emotional impacts included feeling stressed/overwhelmed (67%), depressed/sad (40%), and anxious/nervous (33%). Worries and concerns included worry/concern about the future (100%), concerns regarding child’s physical health (87%), worry about child’s social well-being (80%), concern for child’s emotional well-being (73%), and worry about child being able to function independently (67%). Daily well-being impacts included family strain (60%), missed work time (47%), and missed/limited social activities (33%). Based on the qualitative findings, a preliminary theoretical model depicting the experiences of parents of infants and young children with achondroplasia was created. Conclusions The study sheds light on the range of impacts that parents of infants and young children with achondroplasia may experience, including caretaking responsibilities, impacts on emotional well-being, worries/concerns regarding their child, and impacts on daily well-being. The theoretical model of parent experiences may provide a helpful framework for informing future research and clinical practice.

This study's purpose was to provide qualitative evidence to support the development of two observer-reported outcome measures assessing the physical symptoms/complications of achondroplasia in children and impacts on children's quality of life. Individual/focus group concept elicitation interviews were conducted with parents of children aged 2 to <12 years with achondroplasia and experts. Qualitative analysis of transcripts, based on an adapted grounded theory approach, informed item generation and measure development. Cognitive debriefing (CD) interviews were conducted with parents to confirm relevance and understanding. Thirty-six parents participated in concept elicitation interviews. The analysis identified major physical symptoms/complications and impacts of achondroplasia, which informed the development of the Achondroplasia Child Experience Measures (ACEMs): ACEM—Symptom and ACEM—Impact. ACEM—Symptom was comprised of eight major symptoms/complications including pain (58%), ear infections/fluid in ear (56%), and low stamina/tiring easily (56%). ACEM—Impact consisted of 31 major impacts in the domains of daily functioning, emotional well-being, social well-being, and need for assistance/adaptive devices. Impacts on functioning included difficulty reaching objects/high places (89%) and toileting (67%). Emotional impacts included feeling different (53%) and feeling frustrated/annoyed (47%). Social impacts included difficulty participating in sports/physical play (86%) and being treated as younger than age (83%). Following CD interviews with 16 additional parents, validation-ready ACEM measures were generated. The study improves our understanding of the experiences of children with achondroplasia and provides evidence supporting the content validity of the ACEMs. Validated ACEMs may be used to assess potential benefits of future treatments for comorbidities of achondroplasia.

This study's purpose was to provide qualitative evidence to support the development of two observer-reported outcome measures assessing the physical symptoms/complications of achondroplasia in children and impacts on children's quality of life. Individual/focus group concept elicitation interviews were conducted with parents of children aged 2 to <12 years with achondroplasia and experts. Qualitative analysis of transcripts, based on an adapted grounded theory approach, informed item generation and measure development. Cognitive debriefing (CD) interviews were conducted with parents to confirm relevance and understanding. Thirty-six parents participated in concept elicitation interviews. The analysis identified major physical symptoms/complications and impacts of achondroplasia, which informed the development of the Achondroplasia Child Experience Measures (ACEMs): ACEM-Symptom and ACEM-Impact. ACEM-Symptom was comprised of eight major symptoms/complications including pain (58%), ear infections/fluid in ear (56%), and low stamina/tiring easily (56%). ACEM-Impact consisted of 31 major impacts in the domains of daily functioning, emotional well-being, social well-being, and need for assistance/adaptive devices. Impacts on functioning included difficulty reaching objects/high places (89%) and toileting (67%). Emotional impacts included feeling different (53%) and feeling frustrated/annoyed (47%). Social impacts included difficulty participating in sports/physical play (86%) and being treated as younger than age (83%). Following CD interviews with 16 additional parents, validation-ready ACEM measures were generated. The study improves our understanding of the experiences of children with achondroplasia and provides evidence supporting the content validity of the ACEMs. Validated ACEMs may be used to assess potential benefits of future treatments for comorbidities of achondroplasia.

In the original publication, the summary statistics for child BMI in Tables 2 and 8 were incorrect. The correct version of tables (with updated summary statistics) are provided in this correction.

Background: Little is known about how having a child with achondroplasia impacts parents' quality of life, including impacts on caretaking responsibilities, work, and emotional and social impacts. Aims: The study aimed to investigate the impacts of having a child with achondroplasia on parents and families. Methods: Individual telephone interviews and a focus group were conducted with parents (US and Spain) of children with achondroplasia (aged 2 to <12 years) using a semi-structured interview guide to elicit parents' experiences. Content analysis, based on adapted grounded theory, was conducted to identify themes in the interview transcripts. Results: Thirty-six parents (n=31 mothers; n=5 fathers) of children with achondroplasia participated in interviews/focus group (Spain, n=11; US, n=25), including seven parents with achondroplasia. The most frequently reported caretaking responsibilities related to achondroplasia included managing child's medical care (e.g. appointments, treatment decisions; 92%, n=33), helping child with self-care (e.g., toileting, bathing, dressing; 67%, n=24), and advocating for child (e.g., for school accommodations; 64%, n=23). Helping child with self-care was more frequently reported by parents of younger children (<9 years) compared to parents of older children. Many parents reported missing work time to care for child (50%, n=18). The most frequently reported emotional impacts on parents included worry about child's future (75%, n=27), worry about child's physical health (67%, n=24), concerns about child's safety (50%, n=18), and feeling stressed/overwhelmed (44%, n=16). A majority of parents (69%, n=25) reported new friendships and/or participation in social activities/events through the achondroplasia/dwarfism community as important sources of education and support. Conclusions: This study identified caretaking responsibilities for parents of children with achondroplasia that included assisting child with self-care, managing medical care, and advocating for child. The study also documented impacts on parents' general quality of life, including missed work time, emotional burden due to achondroplasia, and social needs from having a child with achondroplasia.

Searchable abstracts of presentations at key conferences on calcified tissues ISSN 2052-1219 (online)